The Neutrik NAO4MW-FX is a ruggedized and weatherproofed FIBERFOX Adaptor BOX split fiber channel point-to-point connection to extend cable length. Expanded beam fiber optic connectors utilize a lens to expand and collimate the light emitting from an optical fiber. This collimated light beam is transmitted through an air gap to a mating connector, where the light is collected and focussed by a second lens into a second optical fiber to complete the connection. Like shown below.
With 50/125 multimode fiber, the expanded and collimated light beam has an active area of around 3600 times larger than the original 50 µm multimode fiber core.
The effect of collimating and greatly increasing the beam diameter, means that the connector is less sensitive to small particles of dust or other contamination which could completely obscure transmission in physical contact type connectors.